We will continue studies of the action of diamide on isolated tubulin specifically with an analysis of which sulfhydryl peptides are involved in its cross linking. We have found that blocking some key sulfhydryls by alkylating agents prevents cross linking of MAP proteins which is one of the actions of diamide on tubulin. We will continue work on sulfhydryl regulating enzymes, especially glutathione reductase, which in sea urchin eggs have been shown to be regulated by a very low density lipoprotein. We will see if similar regulation occurs in clam and worm eggs and if the changes in activity of GR with mitosis occur in these eggs as they do in sea urchin eggs. We will also see whether the changes in CHO GR which we have found with CAMP occur as a result of a similar regulator protein or if they are due to phosphorlyation of the enzyme. We will also begin to explore other sulfhydryl regulating enzymes such as Mannervik's thiotransferase and thioredoxin reductase-thioredoxin, the latter using NADPH as does GR.